The feet are the foundation and base of support for the entire body, whether standing walking or running. As a result they help protect your bones soft tissue and spine from misalignment and damaging shock forces from the ground. Any weakness, instability or lack of shock absorption in the feet can contribute to postural and stress problems throughout the rest of the body which can lead to knee, hip and back and even shoulder and neck pain.
In the US, foot and foot-related problems affect over 75% of the population. One in six people (43 million people) have moderate-to-severe foot problems. These foot problems cost the US economy about $3.5 Billion/year. Additionally, 16 million people in the US have diabetes, and are very susceptible to problems of the feet. Further, the average age of the US population is continuing to increase. As individuals age, they are increasingly exposed to additional problems resulting from natural, physiological and biomechanical changes such as increasing foot sizes, and various degenerative diseases. The foot continues to change throughout a person's lifetime. With aging, the width and length of the foot often grow by one or more sizes. Collapsing of the arch is also a common occurrence.
As people age there also is a thinning of fat pad tissue of the bottom of the feet. This results in a lack of cushioning and shock absorption leading to increased pain and discomfort. When coupled with certain diseases such as diabetes, this condition can lead to ulceration, loss of limb, or loss of life. Additionally, aging usually results in an increase in body weight which further stresses the skeletal structure. Most people take 8,000 to 10,000 steps per day, which adds up to over 100,000 miles in a lifetime—more than four times the circumference of the earth. The pressure on your feet when walking can exceeds your total body weight, and when you're running, it can be three or four times your weight.
There has also been a trend recently towards more healthy living which has led large numbers of people to undertake daily or frequent walking, running and jogging routines. These usually result in a significant increase in the level of strain placed on the feet.
Since we stand and walk with our feet in contact with the ground, we need to understand the many factors that will impact levels of pain and discomfort while standing or walking for long periods of time such as at the work place.
The weight bearing portion of the body while in the standing position is the foot. This also represents the foundation upon which the knee, hip and back will be affected long term.
As the heel contacts the ground, there is an equal but opposite reaction force from the ground on the calcaneus (heel bone). As a result there is a twisting of the tibial (leg) bone in an inward direction. This forces the arch of the foot lower, making the leg and foot muscles work harder, causing increased muscle fatigue. As a result, any lack of support at the level of the foot will cause the legs to roll inwards and the arch to collapse even further as the work shift progresses. This will cause the hips to tilt anterior & result in a 15 degree trunk forward lean. Knees and hips will also experience more inward stress and strain over time. The back muscles will also be forced to work even harder to keep the worker standing upright
At the same time any lack of shock absorption at the level of the feet allows the force from heel strike to make its way up the body like a shock wave with every step. The harder and more unforgiving the floor or ground surface the greater the shock wave. All the joints and muscles from the ankles to the knees to the hips and the back will feel the effects of this added pounding.
Decrease in blood circulation as a result of prolonged static standing can also lead to swelling of the legs, varicose veins, cramping and increased muscle fatigue and discomfort. The effects aging when added to the equation can also result in arthritis and other degenerative diseases as well as other systemic disorders and medical conditions.
According to Joseph Pine, his book “Mass Customization, The New Frontier in Business Competition.”: ‘the mass production of standardized goods was the source of America's economic strength for generations. But in today's turbulent business environment mass production no longer works; in fact, it has become a major cause of the nation's declining competitiveness.’ As Pine makes clear, the most innovative companies are rapidly embracing a new management paradigm—“mass customization”—which allows them the freedom to create greater variety and individuality in their products and services at desirable prices.
Instinctively, these firms understand that they must adhere to this premise or risk extinction. However, most are simply unwilling or unable to take the necessary action.
In general, mass-produced footwear is often quite uncomfortable, even if perfectly sized. People who value comfort have usually resorted to purchasing specialized more expensive “orthopedic” shoes. Unfortunately, these efforts are generally only marginally effective as orthopedic shoes albeit made with generally softer materials and thicker, softer outsoles are still mass-produced and the unique needs of the individual are still ignored.
Some mainstream footwear companies have realized the need for more precise fitting and now produce footwear in different widths to somewhat accommodate the different foot shapes that are prevalent.
Along the same lines, most athletic shoe companies now produce shoes which fall into three classifications. However, the presence of the three different athletic shoe types is generally misunderstood and ignored except by the even most experienced shoe salesperson and the serious and professional athlete.
The three different athletic shoe classifications are based on the fact that the human foot can be initially subdivided into three major classifications based on arch type. The three classifications are “flat planus foot” or low arched foot, a regular arched foot and a high arched or “cavus foot”.
There are inherent differences in the resulting gait (walking) cycle of each foot type and the associated problems and special footwear needs as a result.
A high arch foot, also referred to as a “pes cavus” foot features an extremely elevated arch. These feet are “supinated” with the heel and toes turning slightly inward and are usually rigid or semi rigid. The resulting poor shock absorption can lead to repetitive stress problems, including pain in the knees, hips and lower back. Foot problems often develop in the heel and forefoot such as plantar fasciitis, arch strain, metatarsalgia and claw toes.
Medium or normal arch feet have a higher arch than a flat foot. Individuals with medium arch feet are usually biomechanically efficient. However, individuals with medium arches are still susceptible to pain and other problems as a result of everyday stress and strain.
The definition of low arch feet or “pes planus” is a condition where the arch is reduced or not present and the entire soles of the feet touch the ground. Low arch feet are typically flexible, over-pronated feet in which the foot rolls inward and the arch collapses under the weight of the body. As a result, over pronation often leads to plantar fasciitis heel spurs, medial knee discomfort, posterior tibial tendonitis (shin splints) and/or bunions.
However, these are just general classifications based on arch height and the exact 3D anatomy and resulting biomechanics as well as the problems that go with them are as unique as an individual's personality.
The different types of footwear themselves can be as diverse as the feet they surround, ranging from high heel shoes, to high top sneakers to steel toed safety boots and everything in between. Each style brings with it a certain level or lack of comfort, cushioning, shock absorption, support and motion control. Even then it is limited and not customized to the individuals needs.
The only alternative to mass produced footwear to accommodate for the different biomechanics inherent in different foot types is custom made footwear. Besides the fact that different types of footwear have different levels of built in cushioning and support, the human foot also changes. Age, pregnancy or any substantial weight loss or gain, other systemic medical conditions or even trauma can also cause the foot to change or function differently which would then require different levels of cushioning and support.
However, custom made footwear is very expensive due to the labor involved in their manufacturing process and a pair of custom made shoes can usually cost between 600-1200 dollars. Custom made footwear is usually prescribed only for extremely deformed feet and it is the insole inside which addresses any biomechanical deficiencies for in addition to sacrificing style, the expense involved in making custom footwear is not adaptable and the expense involved is just not practical for the mass population.
The “insole” is the most important interface between the foot or body and the shoe. It is believed that as much as 80% of the level of “comfort” perceived by the wearer of a shoe may be attributed to the insole. Until recently, most shoes were made with a totally flat inner sole or sock liner which provided little or no comfort, shock absorption or support.
In the last 10-15 years, some footwear manufacturers have started to distribute shoes with a basic contoured insert providing for minimal arch support and cushioning but most manufacturers have focused rather on improving the midsole or outsole. By using these two parts of the footwear, that is the midsole and outsole, that manufacturers have also been able to introduce and hype various marketing gimmicks, such as the “pump”. At the same time, the insole has for the most part gone neglected. The footwear companies have no desire to improve or enhance the insoles that are found inside their footwear as there is no monetary gain to be had due to the fact that the insole has gone neglected for so long, the public has accepted the fact that in order to achieve any serious degree of shock absorption acceptance of after market foot inserts are required.
Market foot inserts fall into two categories; soft cushioning insoles and hard supportive insole/orthotics. The customer is forced to choose between the two types of products and as a result can not get optimal shock absorption and support at the same time. Both types of insoles are usually mass produced and there is very little customization available. This can be problematic, especially when mass produced, one-model, fits-all, harder type, orthotic insoles are sold to the general public, as this type of product can be contra-indicated with the rigid high arch foot type and with certain biomechanical conditions.
The solution of trying to accommodate for different foot types and foot mechanics by using custom-made orthotic device creates similar problems and disadvantages as with custom made footwear. A pair of custom made biomechanical foot orthoses can usually cost anywhere between 250-750 dollars. True custom made foot orthotics have been found to be indicated for less than ten percent of those suffering from foot problems and as a result are not practical for the general population. As the cost of health care continues to rise, insurance companies, employers and individuals are looking for a more cost effective yet customizable solution. The solution lies in utilizing a series of inexpensive semi-rigid arch supports using different angulations and/or material durometers (hardness) and wedges to achieve different levels of support and motion control.
A method of laminating shoe inserts from thermoplastic foam is described in U.S. Pat. No. 4,823,483 to Chapnick.
Various insoles have been developed in order to cater for specific needs, such as described in U.S. Pat. No. 6,481,120 to Xia et al., which is particularly suited to persons suffering from arthritis and diabetes.
One of the disadvantages of prior art insoles is that, generally, they are person or illness specific and not adaptable by the user to suit the level of cushioning and support to suit the person.
Besides different levels of support and motion control needed by each individual due to the hard surfaces, on which the individual stands and walks, especially at the workplace, optimal comfort, cushioning and shock absorption are always required. In a perfect world, optimal cushioning and shock absorption would also be customizable.
There is therefore a need for an inexpensive, removable foot appliance with provides self customizable optimal comfort, cushioning and shock absorption and mass self customized levels of support and motion control using different re-attachable semi rigid supports and wedges.
The same holds true for custom made foot appliances. A pair of custom made biomechanical foot orthoses can usually cost anywhere between 250-750 dollars. To produce custom made footwear or foot orthoses for every type of footwear, or changing foot condition is not practical.
There is thus a need for an inexpensive removable foot appliance which provides optimal and adaptable comfort and shock absorption with re-attachable customizable levels of support and motion control.